<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>第4天JavaScript程序</title>
    <script type="text/javascript">
        var year=prompt("请输入年份","");
            if (year%4==0&&year%100!=0||year%100==0&&year%400==0) {
            alert("闰年");
        } else {
            alert("平年");
        }
    alert("第四个Javascrpit程序。");
        d = new Date();
        document.write(d.toString());
    </script>
</head>
<body></body>
</html>
